On April 8, the RAND Corporation, a nonprofit research institution, released a study on how the Affordable Care Act (ACA) has affected the number of Americans with health insurance. The study found a net gain of 9.3 million Americans with health insurance from September 2013 to March 2014 and that the share of uninsured Americans has dropped from 20.5 percent to 15.8 percent. The report estimated a lower enrollment number than the White House's 7.1 million, but added an important caveat:
“Although a total of 3.9 million people enrolled in marketplace plans, only 1.4 million of these individuals were previously uninsured. Our marketplace enrollment numbers are lower than those reported by the federal government at least in part because our data do not fully capture the surge in enrollment that occurred in late March 2014.
http://www.rand.org/content/dam/rand/pubs/research_reports/RR600/RR656/RAND_RR656.pdf